Danfoss Turbocor TTS Series Service Manual page 256

256 of 282
M-SV-001-EN Rev. G
• If DC Bus voltage is correct, proceed to Step 13.
• If DC Bus voltage is not correct, verify the SCRs.
• If the SCRs pass test, replace the Soft Start then repeat Step 13.
• If one or more of the SCRs test faulty, replace all three of the SCRs then repeat Step 12.
13. Verify the 15VAC through the test harness (Potted DC-DC only).
• If the 15VAC is present, proceed to Step 14.
• If the 15VAC is not present, replace the Soft Start then repeat Step 13.
14. Isolate the compressor power as described in Section "1.8 Electrical Isolation" on page 19 of
this manual.
15. Remove the DC-Bus test harness and re-install the J2 (250VDC) and J3 (24VDC) (Potted DC-DC)
or J4 (24VDC) Open Frame DC-DC) outputs to the DC-DC Converter.
16. Re-install the top covers and remove the Service Side Cover.
17. Re-apply compressor power.
18. Verify the 250VDC and 24VDC test points on the Backplane.
• If both voltages are within +/- 10%, all supply voltages are good.
• If either voltage is not within +/- 10%, proceed to Step 19.
19. Isolate the compressor power and wait for the LEDs on the Backplane to go out.
20. Remove all connectors from the Backplane, leaving only the J6 (Inverter cable), J4 (250VDC)
and J24 (24VDC) inputs connected.
21. Remove the Serial Driver (refer to "4.27.4 Serial Driver Removal and Installation" on page 213)
, BMCC (refer to "4.28.4 BMCC Removal and Installation" on page 217) and PWM (refer to
"4.29.4 PWM Removal and Installation" on page 221).
22. Re-apply compressor power.
23. Verify the HV+ and the +24 VDC test points on the Backplane.
• If all voltages are within +/- 10%, proceed to Step 26.
• If either voltage is not within +/- 10%, isolate compressor power and wait for the LED's on
the Backplane to go out, then disconnect the J4 and J24 connectors from the Backplane.
24. Re-apply compressor power.
25. Verify the 250VDC and 24VDC at the J4 and J24 DC-DC Converter output connectors.
• If either voltage is not within +/- 10%, replace the DC-DC Converter.
• If all voltages are within +/-10%, replace the Backplane.
26. Verify the +17V, +15, +5 and -15 VDC test points on the Backplane.
• If all voltages are within +/- 10%, proceed to Step 27.
• If any voltages at the +17V, +15, +5 and -15 VDC test points are not within +/- 10%, replace
the Backplane.
27. Isolate the compressor power and wait for the LEDs on the Backplane to turn off, then re-install
all connectors and the PWM (refer to "4.29.4 PWM Removal and Installation" on page 221) ,
BMCC (refer to "4.28.4 BMCC Removal and Installation" on page 217) and Serial Driver (refer to
"4.27.4 Serial Driver Removal and Installation" on page 213) to the Backplane.
28. Re-apply the compressor power.
29. Verify the +17V, +15, +5 and -15 VDC test points on the Backplane.
• If all voltages are within +/- 10%, all supply voltages are good.
• If any of these voltages are not within +/- 10%, refer to "5.5.2 Determining the Cause of an
Energy Drain".